It is right for British people to employ immigrants as long as they want to "work hard and get on", David Cameron has said.

The Prime Minister launched a passionate defence of his decision to hire a Nepalese nanny, a week after James Brokenshire, the immigration minister, blamed the middle classes' demand for cheap foreign labour for fuelling migration.

He said Gita Lima, who cares for his three children, does a "fantastic" job and she wants to improve her status in life.

He laughed off suggestions he may have helped her gain British citizenship with a joke at the expense of his Cabinet.

Last week Mr Brokenshire, blamed a "metropolitan elite" for fuelling migration - a comment that immediately brought scrutiny on his ministerial colleagues, many of whom employ foreign cleaners.

But Mr Cameron indicated that he has no problem with foreign employees if they aspire to a better life.

Mr Cameron has said he wants to bring immigration down to the "tens of thousands", but net migration last year was in excess of 200,000.

Asked whether he had given up trying to bring immigration down, starting by employing a British nanny, Mr Cameron said Ms Lima is an "excellent woman".

"She is a British citizen, she came originally from Nepal, she carried out her exams to become a British citizen. She does a fantastic job and she certainly fits the description of someone who wants to work hard and get on."

However, Mr Cameron joked that he did not help her with the Home Office tests that quiz would-be citizens on their knowledge of life in Britain.

"I can confirm as well that I didn't give her any assistance in these ,exams you have to take to become a British citizen," he told a press conference at the end of his two-day visit to the Middle East.

"She did once ask me one of the questions in the exam: what is the role of the British cabinet?

"I won't share with you the answer I gave but I'll leave you to speculate."

New polling by Ipsos MORI today shows trust in the government on immigration has fallen. Just 12 per cent of voters think politicians are "open and honest" about it, with 76 per cent disagreeing.

Mr Cameron said he thinks immigration is still "too high and needs to come down", but said immigration from outside the EU is at its lowest level since 1998 thanks to a crackdown on bogus marriages and students.